1. Field of the Invention
The present invention relates to an apparatus and method for improving the imaging of tissue using a catheter for accessing, imaging and manipulating a body cavity in general, and to a catheter that has an imaging unit which emits and receives electromagnetic radiation or acoustic energy, and where such electromagnetic radiation or acoustic energy is utilized for imaging, locating and manipulating biological tissue.
2. Discussion of the Related Art
In 1806 Bozzini introduced the first instrument for electromagnetic radiation assisted visualization of a bodily cavity. He devised the first Cystoscope. For approximately 200 years, the principle remained the same; a catheter with light source at one end and a set of lenses to transfer the images to the operator. Almost a hundred years later, in the late 1800's, the discovery of X-rays by Reontgen and Tesla led to the development of a new field in medicine called radiology. The discovery of X-rays has led to development of various imaging devices operational at a distance from the body. These devices include X-ray, Fluoroscopy, CT and the like. Marie curie's discovery of radiation emitting elements in the late 1800's together with the invention of Anger's gamma camera, some 60 years later, have led to the development of nuclear medicine. Nuclear medicine is used for therapy as well as imaging. Imaging is performed by detecting traces of radioactive emission and scattering. Nuclear medicine was used in medicine primarily to determine function rather than anatomy of an organ.
During the late 20th century the use of imaging catheters using visible light source and cameras invaded almost any body cavity or organ. These included the bowls, gynecological, respiratory, CNS and others. Blood vessels were not candidates for visible light and camera catheters due to their thickness, which is around 10 mm's. Blood vessels were imaged using a process called angiography. In Angiography, a catheter is introduced into a blood vessel and is advanced until the relevant area is reached. At this point Contrast material (substance with heavy Z element) is injected into vessel lumen while X-ray imaging is performed to image the outer contour of the vessel. Several drawbacks of the technique include; the use of nephrotoxic elements, poor imaging quality, limitations in three dimensional imaging due to observer view perspective. There is therefore a need in the art for intravascular imaging tool and technique that will reduce the need for heavy Z contrast material and that will increase sensitivity of imaging resolution. There is also the need for intravascular imaging that will allow a vascular surgeon to image the blood vessel wall with greater accuracy.
Other intra-cavity scopes using visible light source also have several disadvantages; they require a clean organ cavity and clear view to a target. The use of the recently developed autonomous intra-cavity imaging camera did not answer these issues. Some of these issues were answered by the use of sound wave technology to view intra-body and intra-vascular spaces. The use of Ultrasound (US), however, is limited as well since sound requires a fluid medium to be transmitted. Thus, ultrasound imaging is not available in air containing intra-body cavities such as the respiratory system and parts of the gastrointestinal tract. In addition, in the same manner as with light, sound is deflected by debris and inflammatory tissue. This may reduce imaging quality and depth in various inflamed tissues.
Today, imaging of the body can be realized in various formats from many different positions, using an array of instruments. However, some locations and situations still constitute a challenge. These include, inflamed, debris filled spaces. For example, unclean or inflamed Colon, chronically inflamed facial sinuses, inflamed middle ear and others. The unparallel move towards minimal invasive surgery demand from the surgeon to perform tissue manipulations in small dark and often debris filled spaces were imaging often becomes difficult. External imaging frequently fail to illustrate the three dimensional environment where a surgeon will work during an operation. In location where conventional imaging using visible light source and camera as well as US technology are ineffective, a need for an imaging device that will help the physician to perform tissue manipulation exists.
There is therefore a need in the art for an apparatus and method which allow better and enhanced imaging of internal parts of the body organs, cavity or tissue. This imaging apparatus should allow the operator to visualization anatomical and histological structures at locations where visible light imaging is imperfect, inadequate or impossible. There is also the need in the art for an in-organ or body cavity imaging system which allow for imaging of tissue beyond the range of visible light imaging. There is also a need in the art for imaging inside a body organ or cavity where imaging quality is unaffected by inflammatory tissue elements or foreign debris. Such a method will allow an operator to receive important information beyond what can be seen with the available visible light imaging devices and methods used today.